Tube sign construction



S. SONKlN TUBE SIGN CONSTRUCTION June 14, 1938.

Original Filed Sept. 27, 1932 I ATTORNEY.

Patented June 14, 1938 PATENT OFFICE TUBE SIGN CONSTRUCTION Simon Sonkin, New York, N. Y., assignor to Samuel 0. Miller, New York, N. Y.

Application September 27, 1932,. Serial No. 635,090 Renewed October 30, 1937 11 Claims.

This invention relates to so-called electric tube signs; more particularly, to constructional installation features in wiring and operating the same.

In the operation of so-called electric tube signs, or neon gas signs, comprising gas filled tubes formed into letters or characters, now widely in use and operating under high voltage, serious servicing problems are involved, especially where these signs are exposed to the weather in outdoor operation, by reason of failure of the insulation used adjacent the contacts holding separable tube elements. In the large Signs comprising separate tubes formed into characters, failure in the insulation at any point very frequently exhibits the entire sign assembly in an objectionable manner, due to flickering, without any indication as to the point of failure, thereby consuming considerable time, labor and expense in its repair or renewal to operating conditions. Maintenance of improperly operating units and the conditions referred to is accompanied by high intensity sparks, particularly adjacent the electrodes of the tubes, which very quickly disrupt these more expensive parts of the sign or the essential parts of the assembly to make replacement and repair an expensive item of cost. I

It is therefore an object of my invention to provide an electric tube sign construction; and in connection with the wiring circuit for operating the same, of safety measures which will assure long life and the proper continued operation of the electric sign, assembly or any portion 0 thereof, so that upon failure of the insulation,

due to extraneous elements, erosion, perforation, cracking resulting in the breaking down of the insulation, the disruptive action of the'shortcircuiting resulting from such failure will have the minimum, or substantially no deteriorating eifect upon more costly portions of the sign assembly.

It is therefore contemplated by me to include in electric tube signs of the character operating under high potential, and known on the market as neon tube signs, of a safety device which will minimize or eliminate any disruptive tendencies in the operation of the sign, due to failure in any portion thereof, and to further provide an installation which will readily indicate the points of failure, should they occur, so that replacement and repair may be facilitated.

It is still further contemplated by me as an object of my inevntion to provide in an electrical installation such as that used for operating electric gas tube signs operating under high potential, of a circuit control mechanism which serves to shunt the current flowing through an electric sign or portions of the installation operating under faulty conditions, which may be occasioned by failure of insulation, improper adjustment of contacts or imperfection in any portion of the installation, to eliminate the disruptive effect of short circuits through the more fragile or expensive portions of the sign or any element thereof. It is contemplated by my invention to provide in an installation operating under high potential, particularly an electric gaseous tube sign construction of mechanism forming part of the electric circuit, which responds to the heat generated by sparking, to minimize or eliminate the disruptive tendencies of short circuiting, in the more vital parts of such sign installation.

Still further objects of my invention reside in the provision of an installation for use in connection with electric gas tube signs which, under proper operating conditions of the tube elements, and the electrical circuit feeding the same, is inactive, but which upon failure or the development of any defects in the installation, causes the current to be diverted from the defective part or connection, to avoid damaging of more fragile parts, readily susceptible to damage by high potential sparks.

To attain these objects and such further objects as may appear herein or be hereinafter pointed out, I make reference to the accompanying drawing, forming a part hereof, in which- Figure 1 is a fragmentary sectional view and diagrammatic wiring installation showing my invention;

Figure 2 is an enlarged detail, partly in longitudinal section, of a thermal-responsive'spark gap switch;

Figure 3 is a plan view thereof;

Figure 4 shows a fragmentary enlarged detail of another embodiment of my invention in assoelements may be formed into letters, characters 'or other representations, in accordance with the electrodes i2, through the exterior contactci ng base I, may be positively connected in the s kets I I.

Preferably, however, forpurposes of effecting best insulating conditions, the contacts I are mounted in spaced relationship within the sockets H and are held in this spaced relationship from the walls of the sockets by the standards l1, connected to the sheet III by suitable fastening means H8. The free ends of the standards ii are preferably made of insulating material and provided with a tube conforming rider ID, to which the tube is fastened by a twisted wire, as shown at 20.

For the installation as disclosed, I provide a thermal switch A, shown in detail in Figures 2 and 3, and in my preferred form comprises an insulated member 2|, one end of which supports a binding post 22, anchoring in spaced relation to the insulating member ii, a bi-metallic heat responsive conductor strip 23, rigidly connected to the binding post 22, as by suitable fastening means, such as a screw 24, though spot welding,

' brazing or similar rigid fastening means may be employed. The bi-metallic conductor 23 is so positioned that the layer 2! lies innermost and comprises a metal of low coefficient of expansion. The outer layer 26 is disposed away from the insulating member 2i and is of a material which has a relatively high coefficient of expansion, when subjected to heat. These two layers 25 and 28, are riveted or otherwise fastened together, in close contact, to avoid any independent action. As the nature and compositions of the separate layers may be varied depending upon operating conditions, these materials maybe varied to suit the individual purchaser. I have found that excellent results may be obtained by makingthe layer 25 of invar, a nickel-steel alloy, and the 'layer 26 of brass.-

The end 21 of the insulating member is provided with a combined terminal binding post and set screw 28, carrying at the outer end a tip 28 of spark resisting, electrical contacting material. This is disposed oppositely to the free end of the bi-metallic/element 23, which also carries on its inner surface, a small contact point 32 of spark resisting electrical contacting material.

Thermal switch A as provided and illustrated in Figures 2 and 3 may be, suitably enclosed in some jacket of glass or otherwise, to keep out dirt or dust particles, .and may be so installed in the sign assembly as an independent unit wherever desired 01' which the following is an illustration.

Referring now to Figure l, a source of elec-' trical alternating current C, serves to operate through a transformer T, the feed being to the primary circuit thereof. From the secondary circuit 8, connected with the terminals 3i and 22, there is provided conductors 33 and 34 connected to the most remotely positioned binding posts I of the tube elements, and where as in the construction illustrated, a plurality of such tube elements are connected in series, an intermediate conductor 3! serves to electrically connect the intermediate binding posts it. The sheet I! is grounded as shown at G. pref ra ly also grounding the transformer at the conductor 30, running to the mid-point M of the secondary circuit thereof. I

with a circuit as just described, the electrical tube elements 13 are connected in series, though it will be readily understood that these elements may be connected in parallel, in accordance with the necessary potential for operating the electrical gas tubes.

Connected with each pair of terminals iii of the cooperating electrodes l2, for each of the tube elements, and in parallel with the tube elements, I interpose a thermal switch A, preferably connecting the terminals 22 and 28 by intermediate conductors 31 and 38. As many thermal switches as desired may be incorporated in the circuit just described, as there are separate tube elements, so that each tube element has an independent shunt circuit in which the thermal switch is interposed.

The thermal switch is adjusted so that the gap between the points 28 and 30 is normally open, at normal atmospheric temperatures. The gap between the points 29 and 30 is so adjusted in relation to the tube element IS, in parallel therewith, that under normal operating conditions, the resistance across the gap formed by the points 29 and 30 is considerably higher than the resistance necessary to properly operate the tube elements l3. The gap, however, is so adjusted that the resistance of high potential current across the gap is materially lower than that which may flow through a cracked or impaired insulating socket ii, and the most adjacent section of the panel I0, or in fact, the resistance across the gap 29 and 30 is so adjusted that it is lower than any point of failure where sparking may occur, due to improper mounting, imperfection, shorting caused by moisture, after rain, adjacent the electrodes E2 of the various tube elements.

In operation, any imperfection adjacent the electrodes, due-to failure 01' the insulation between the electrode l2 and any part of the supporting mechanism therefor, which would otherwise, on continued operation, cause a flickering in the sign element, and sparking adjacent the rent jumping the gap between the contacting.

points 28 and 20, and the consequent formation of a spark. As a result thereof, the current will flow through the bi-metallic element 23 and the composite strip will be heated. During this action, the movement of the free end of the strip 23 will serve to reduce the spark gap and therefore divert the current through the thermal switch including the conductors 31 and 28, rather than have it flow through the electric tube element II and the circuit thereof. As the bimetallic element 22 is heated to a greater extent, the contact points 2! and SI, are brought into positive engagement, thereby completely diverting the current through the thermal switch. As the spark is reduced, thetemperature of the bi-metallic element 22 diminishes, the spark gap ing the other elements free to operate in the normay way. Should the condition tending to cause ashort circuiting adjacent the electrodes be a temporary one, as by the entrapping of water after rain, upon drying up of the contact adjacent the electrode, the normal resistance at this part will be re-established, and the current may again flow through the tube element, rather than through the thermal switch.

Should conditions arise which actually pennanently impair the electrical circuit adjacent the electrodes of the tube elements, the intermittent action caused by the variation of the spark gap between the contacts 29 and 30, particularly where a thermal switch is provided for each tube element as the temperature of the bimetallic element 23 varies, will serve as an indication for the repair man, to determine which element of thesign assembly requires adjustment, repair or replacement rather than necessitating the inspection of all the elements of the entire assembly.

By having the thermal element control the spark gap, under normal operations, the spark gap may be adjusted for a distance which is considerably in excess of the resistance of the circuit through a tube element l3. The initial spark which may be formed across the gap of the contacts 29 and 30 may, under these conditions, rapidly erode and burn the contact points. However, this effect will be quickly minimized and reduced by the thermal action of the bimetallic member 23, which greatly reduces the spark gap until intimate contact is made between the points 29 and 30, thereby reducing the erosion efiect of the spark.

Under certain conditions of operation where a single continuous tube element constitutes the sign, I may position across the terminals 3| and 32 of the secondary circuit of the transformer, a thermal switch A, through the circuit 39, preferably interposing a resistance element 40. This connection may also optionally be included wherever thermal switches are used for a plurality of sign elements, and when so used, adds a large safety factor to the entire system generally, and specifically to the transformer T.

In the installation previously described, the thermal switch has been described as connected in shunt or parallel with the sign tube elements. I may, however, accomplish desirable operating 'conditions, to. save the deteriorating effect of sparks, by connecting a somewhat similar element in series with each of the conductors feeding the electrodes. For this purpose, as illusstrative of such embodiment of my invention, reference will now be made to Figure 4 which shows the electrode end I! of a tube element i3 formed with a contacting base l4. This is preferably fitted within a tubular sleeve 4i, partially split at 42 to make resilient engagement with the base l4. The sleeve 4| has a pigtail 43, soldered thereto and connected with a terminal 44, mounted upon a slidable plate 45, held against rotation within a socket 46, made. of insulating material. Forked portions 41 engage a rib 48, to hold the plate against rotation, but permitting sliding movement. The terminal has its lower free end formed with a contact point 49, terminating between the arms of the loop 50. Within this loop, there is positioned a coiled metal spring 5|, formed oi'a bi-metallic couple, the elements whereof have different .thermal coeflicients of expansion. The upper end 52 of the coiled element 5| is provided with a layer of sheet of heat abutments 56, formed in the walls of the socketso that in normal operation, the contacts 49 and 53 are held urged against each other, but complete the circuit feeding the tube elements.

Should these become eroded causing the forma-' tion of sparks at this point, during operation, the sparking action will heat the coil 5|. The bi-metallic material, under these conditions, will shift the position of the end of the coiled' element, thereby presenting a new portion of the contact 53, mounted thereon, in relation to the contact point 49. This operation will serve to prevent burning out and wear of the contacting portions 49 and 53, thereby permittingthe use of less expensive alloys for the contacting material, and avoiding rapid deterioration of these elements.

In Figure 5 I have disclosed another embodiment of my invention, in which a supporting base 51, made of insulating material, supports a terminal or binding post 58, forming part of the electrical circuit. To this terminal there is mounted a bi-metallic strip 59, made of metals having widely varying coeillcients of thermal expansion. The free end 60 is bifurcated, and between these furcate portions there is mounted an insulating block 6|. This block rides against a loop 62, of the bracket 63, against a spring leaf or latch 64. The bracket carries a terminal 65, serving as a means of connecting a conductor forming part of the electrical circuit. The terminal 65 carries a threaded screw 66, which in turn carries a contact point 61. oppositely disposed to the contact point 61, and mounted upon the bi-metallic strip 59, is a contacting point 68. In normal operation, the contacting points 61 and 68 are held in spaced relationship. Under conditions wherein sparking may occur between the contacting points 61 and 68, for reasons occurring in the sign tube construction as previously described, the bi-metallic strip 59 will be warped, to urge the contacts 61 and 68 into closer relationship, until final contact is made. In this position, the spring member 64 will snap beneath the block 6 to permanently hold the contacts 61 and 68 in engagement with each other. This form .of insulation may be mounted at some convenient point in the sign assembly, which may be accessible, so that when repair or replacement is made, the operator will merely have to unlatch the spring latch 64, and permit the bi-metallic leaf to assume its normal position, with the contacts 61 and 68 in spaced relationship, and after alteration, repair or replacement has been made, the sign assembly is again in condition for proper operation.

It will be understood that the length of the bimetallic elements in the thermal switches, as described, may be made of such size and dimensions as to obtain the requisite deflection and warping two bi-metallic elements operating'in opposite directions.

It will further be observed that though I prefer to use the bi-metallic strip for my thermal switch element,other thermally responsive means such as aneroid diaphragms may be used with some suc= cess and obtain somewhat equivalent operation.

It will thus be observed by the device and installation as described, that electric tube signs may be operated with a large measure of safety, to avoid the destructive eilects oi high potential currents, due to failure or improper arrangement 01' any of the parts, with convenience oi adjustment; replacement and repair, when necessary, as

the thermal switch included in the installation A will clearly indicate the points of the assembly requiring attention.

The detailed features of the embodiments of my invention relating to the switch construction are claimed in my application Serial No. 2,883.

Having thus described my invention and illustrated its use, what I claim as new and desire to secure by Letters Patent, is:

1. In a high potential, electrically operated assembly of the character described, electrical conductors connected with an electrical source for operating the same, a separate circuit in electrical parallel connection with said assembly, including electrode points normally spaced from each other to form a gap of a resistance higher than that necessary to properly operate the assembly, means for moving said points into the open or closed position automatically by variations in temperature responsive to sparking across the gap to decrease the resistance 01' said gap to and including positions closing the gap, and under diminished temperature to open the gap to the normal spacing of said points.

2. In a high potential, electrically operated gas tube, sign assembly, electrical conductors connected with a source of energizing current for said sign, a separate shunt circuit for said sign including a thermally-responsive and controlled variable gap, normally open and of a resistance greater than the sign assembly, contacts for said gap, one 01 said contacts being mounted to reestablish the normal resistance automatically.

3. Ina high potential, electrically operated gas tube sign assembly, including a plurality of tube elements having separate electrodes, conductors for said electrodes connecting said sign elements in series, a-source of energizing current for said sign assembly, separate shunt circuits for each of said sign elements, said shunt circuits including electrode points normally spaced from each other to form a gap of resistance higher than that necessary to properly perate the tube elements, mounting means for said points, said mounting means being variable to diminish the conditions resulting in low temperatures of said. 85

spark gap under current flowing through said mounting means to andincluding positions closing the gap at *high temperatures and automatically re-establishing substantially the gap .under mounting means.

, 4. In a high potential, Ielectrically operated gas. tube sign assembly, electrical conductors con- 'nected with a-source ot-energizing current for said sign, a separate shunt circuit-tor said sign including electrode points normally spaced from each other to form a gap of a resistance greater than the sign assembly, one of said points being mounted'upon a bi-metallic element responding to flow oi current through said gap. to decrease the resistance or said gap'and to cause the flow of current through said gap progressively as the resistance is reduced.

5. In a high potential, electrically operated gas tube sign assembly, electrical conductors connected with a source of energizing current 101' said sign, a separate shunt circuit for said sign including electrode points normally spaced from each other to form a gap of a resistance greater than the sign assembly, one of said points being mounted upon a reversibly movable bimetallic element responding to flow of current through said gap, to decrease the resistance of said gap and progressively cause the flow of current through said gap as the gap resistance is reduced under the heat generated, the reduction being a i'unction oi the variation in temperature in said element, and urge said points into contacting engagement.

6. In a high potential, electrically operated gas tube sign assembly, including a plurality of sign elements having independent electrodes, electrical conductors connected with a source of energizing current for said independent sign elements, connecting said elements in series, a separate shunt circuit for each of said elements, electrode points in said shunt circuit, normally spaced from each other to form a gap oi. a resistance higher than that necessary to properly operate said independent elements, and a thermal switch for molmting said points in relative position to each other, automatically inversely proportionally to the temperature. existing across said gap by reason or absence oi' sparking thereover, to and including the closed position 0! said gap.

7, In a high potential, electrically operated assembly of the character described, electrical conductors connected with a source of energizing current for said assembly, contacting connectors between said conductors and said assembly, one

mounting means for d points responsive to sparking and the he generated thereby, to change the contacting surface for said points in increments of position controlled by the heat generated.

8. In a high potential, electrically operated assembly 01' the character described, electrical of said connectors inctlrilding contacting points, t

conductors for said assembly connected with a tions of said points.

9. In combination, a gas discharge tube, means to supply current to said tube, a pair of contacts forming a gap connected in shunt with said tube,

' and a thermostat element mounted to move said contacts toward contacting position in response to heat generated by discharge current across said gap.

10. In combination, a plurality of gas discharge tubes connected in series and to a source of current, and a shunting device connected across the terminals of each tube comprising a pair oi. contacts forming a-gap and a thermostat element mounted to move said contactstoward contacting position in response to heat generated by discharge current across said gap.

11. In a device of the character described, operable by a low current under a high potential, 8. thermal switch for the protection thereof, said switch being operable to its closed position by heat generated by an arc across the gap formed by its normally spaced contacts and comprising.

a pair of normally spaced contacts of an are resisting material and forming an arc gap therebetween, means for carrying one 01 said contacts and maintaining the same in fixed position and a bar comprising a composite bi-metallic strip and fixed at one end and carrying'the second contact at the other end, said bar having its metallic l0 strip having a low thermal coemcient on the side formed by said contacts will heat said bar and cause the same to move to close the gap and extinguish the arc and the consequent cooling will cause the bar to move to an open position thus returning the switch to its normal condition.

smon somrm. 

